Truly, madly, deeply

When Kim rejected my pimply, gangly persona for the dashing, athletic Nicholas in third form, I felt an exquisite agony, like open-heart surgery without the anaesthetic.

Forty-one years later, my memory of it is thankfully imperfect, but I’m pretty sure that at the time, I couldn’t see the point of living. Had I known that I might well have been suffering takotsubo cardiomyopathy­—broken-heart syndrome—and that my brain had released chemicals that, among other things, were enfeebling my heart tissue, that my serotonin levels had plummeted, that my secondary somatosensory cortex and dorsal posterior insula were in overdrive trying to process feelings of social rejection, that my anterior cingulate cortex was whipping my vagus nerve into spasm, causing me real physical pain, nausea and cramps in the chest, I doubt I would have cared less.

For most of history, love has been the obsession of the arts, which present it to us as some hazy, visceral force, a universal currency so enriching that even John Lennon believed, apparently, that we need nothing else.

Love has ever been intangible, but nowadays imaging technology has become so percep­tive that we can finally see it, writ large as firework flashes across a brain-activity scan.

When I first gazed upon my beau across roll call, I felt something entirely novel and bewitchingly compelling. A romance writer would have called me smitten, but any neuroscientist would have recognised some familiar patterns on an oscilloscope. My naive evolutionary psyche was grappling with its first experience of the mating ritual, an imperative I barely understood. My brain had released a cocktail of potent hormones, neuropeptides and neurotransmitters as my genes issued a courting order. They had a three-point plan: I was on the brink of stage one, known to the earthy as lust. I was awash with testosterone. Acting alone, it would merely compel me to attempt mating with practically any female—but my singular obsession with Kim was sparked by electro stimuli in the nucleus accumbens and ventral tegmental areas of my brain, releasing intoxi­cating dopamines.

Lennon would have said I was lovestruck; a psychologist would tell you that I was now a drone, controlled remotely by the neuro­transmitters coursing through my synapses. Vasopressin washed into my ventral pallidum and oxytocin into my paraventricular hypotha­lamic nucleus—endorsing my mate choice. Of course, I was far too young to even conceive, let alone advance, the sexual negotiation that so often follows in adult congress. Our genes reward us for doing things that keep them alive and replicating, which is why eating and sex are so much fun. If we do their bidding, genes make sure we enjoy it by ordering the release of feel-good hormones: the broth of stimulants flooding our sated bodies after sex—serotonin, oxytocin, vasopressin and endogenous opioids—grants us an afterglow uncannily similar to a shot of heroin (opioids are the body’s natural analogue).

Love is not so much a feeling as a chemical high produced by a cocktail of hormones acting on different areas of the brain. Electric stimulation produces dopamine, which we associate with feelings of pleasure, an increase in motivation and a corresponding decrease in rational thinking. Vasopressin—associated with sexual attraction—is the primary ingredient in feelings of lust, and oxytocin—also released during breast-feeding to increase the connection between mother and child—creates the bond for the final stage of romantic love, attachment.

This buzz can also help to cement a bond with our lover, at which point we enter the second stage of love, attraction. This is, for the stricken party, a time of exhilaration, almost delirium. For others in proximity, it can be nauseating: I thought of nothing else, nobody else, than Kim for months on end. I didn’t hear a word the teacher was saying.I was obsessed, literally, and, it turns out, chemically too: spikes of adrenaline, norepi­nephrine and cortisol caused butterflies in my stomach, prime symptoms of anxiety. In fact, behaviourists have pointed out the similarity between lovestruck people and obsessive compulsives—certainly both show the same serotonin levels. An Italian study in 2005 also found that a certain protein molecule, known as nerve growth factor (NGF), shot to satura­tion levels in people experiencing newfound romantic love. When asked to rate the inten­sity of the love they were feeling, their scores agreed with their relative NGF levels.

At least one study hints that we can replicate love in the lab: Professor Arthur Aron at Stony Brook University in New York State showed that volunteers, complete strangers to one another, could experience feelings of ‘love’ after as little as 30 minutes, simply by sharing intimate insights into their lives and staring deeply into one another’s eyes for four minutes without talking. Some subjects later reported a deep connection and attraction. One pair ended up getting married.

When Kim finally replied to one of my love notes (I’d get to school early so I could leave them in her desk), I surfed a tsunami of dopamine. I wafted about on a cloud of exclusive, intense focus, boundless energy and sheer bliss.

Oxytocin, the ‘cuddle chemical’ also released in breast-feeding mothers, sent notes to me: ‘She’s the one.’ As songwriters well know, my heart rate hit triple figures (when, I assume, it starts going boom-biddy­boom), almost as though I’d taken amphetamines, which, as it happens, trigger the same biochemical response.

The rewards and stimulation of the attrac­tion phase—or, conversely, the anti-climaxes and letdowns—help us to decide on our evolutionary running mate, the most suitable partner with whom to take the next critical steps. But this heady romantic reverie, to our collective disappointment, almost always subsides after a year or so. It’s a poor plat­form for child-raising, which is why we need a third stage—attachment—to seal the deal.

Behaviourists recognise attachment as a very different kind of love—more compassion than passion, less about delirious trysts and more about an enduring contract based on mutual commitments such as marriage and child-rearing and shared beliefs, pastimes and interests. Now, the body steps up our doses of oxytocin and vasopressin to instil security, social ease and emotional union. The aforementioned Italian study, when it retested subjects a year after they had fallen in love, found their NGF levels had returned to normal.

Love cannot hide from the gaze of functional magnetic resonance imaging (fMRI), which can monitor regions of brain activity. Yet the result is far from clear. Many regions of the human brain are active during a love experience, but different areas of activity correspond to passionate love and other forms of love, such as compassion and attachment.

Divorce statistics would seem to prove that even powerful hormones cannot always deflect the temptations and frustrations of modern life. For all its sophistry, our on-board mating control system appears to contain a critical flaw: it seems we can experience all three love stages independently and, more’s the pity, concurrently. People who insist that you can be in love with more than one person at a time could be onto something. Certainly, we can at least be infatuated enough—even temporarily—to derail an attachment bond.

In our defence, we learn from experience, or at least some of us do. By adulthood, mate selection is no longer about blind compliance to some primal urge: we apply real-world expe­rience to filter prospective mates. We carry an innate list of desirable traits and check them off one by one on that crucial first date.

Intuition has proven a poor matchmaker:if you’re still waiting for your ‘soulmate’, the missing piece of your emotional jigsaw, you’re wasting time and opportunity. Research into the very different partner choices made by identical twins shows us that success comes instead from learning and level-headed application—the very opposite of what our genes counsel.

Kim and I, however, never made it to attachment—at 13, we were experiencing only the first fitful coughs of a genetic imperative in boot-up. Our chemistry was rampant, but wrong. I don’t know why I put myself through the misery of going to the third-form ball, just to sit and watch her and Nicholas dance and flirt; perhaps my anterior cingulate cortex made me do it. All I knew was that my world was burning. And then Wendy walked up and asked me to dance. I felt a familiar rush…